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Image/Video Coding Techniques for IPTV Applications

Image/Video Coding Techniques for IPTV Applications. Wen-Jyi Hwang ( 黃文吉 ) Department of Computer Science and Information Engineering, National Taiwan Normal University, Taipei, 117, Taiwan. Goal of This Talk. Overview of Image/Video Coding Techniques for IP TV Applications

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Image/Video Coding Techniques for IPTV Applications

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  1. Image/Video Coding Techniques for IPTV Applications Wen-Jyi Hwang (黃文吉) Department of Computer Science and Information Engineering, National Taiwan Normal University, Taipei, 117, Taiwan

  2. Goal of This Talk • Overview of Image/Video Coding Techniques for IP TV Applications • Image Coding: JPEG, JPEG2000 • Video Coding: H.261, MPEG1, MPEG2, H.263 , MPEG4, H.264

  3. WHY Compression ? SDTV broadcasting~2Mbps ITU-R 601 166 Mbps ~ 100 : 1 DSL ~200 kbps ~ 1,000 : 1 Dial-up modem, wireless link ~ 20 kbps ~ 10,000 : 1

  4. Image Coding Techniques • JPEG (Joint Photographic Experts Group) • DCT-Based Technique • Published in 1992 • JPEG2000 • Wavelet-Based Technique • Published in 2000

  5. Principles of Image Coding Technique Color Transform DCT/Wavelet Quantization Bitstream Formation

  6. Color Transform (JPEG) • Process the data in blocks of 8×8 samples • Convert RGB into Luminance (Y) and Chrominance (Cr and Cb). • Use half resolution for Chrominance (because eye is more sensitive to Luminance)

  7. DCT (JPEG) • Transform each block of 8×8 samples into 64 DCT coefficients • energy tends to be concentrated into a few significant coefficients

  8. Quantization (JPEG) • Divide each DCT coefficient by an integer, discard remainder • Typically, a few non-zero coefficients are left.

  9. Quantization (JPEG)

  10. Wavelet Transform (JPEG2000)

  11. Wavelet Transform (JPEG2000)

  12. Quantization(JPEG2000)

  13. Quantization (JPEG2000)

  14. Quantization(JPEG2000)

  15. Quantization (JPEG2000)

  16. Quantization for Resolution- Scalable Transmission

  17. Quantization (JPEG2000)

  18. Layers 1+2 Layers 1+2+3 Layers 1+2+3+4

  19. Quantization for SNR-Scalable Transmission

  20. JPEG2000-Based Layered Transmission

  21. JPEG2000-Based Region of Interest (ROI) Encoding

  22. Comparisons (JPEG and JPEG2000) JPEG2000 (64:1) JPEG (64:1)

  23. Video Compression-History “It has been customary in the past to transmit successive complete images of the transmitted picture.” [...] “In accordance with this invention, this difficulty is avoided by transmitting only the difference between successive images of the object.”

  24. Features of Moving Pictures • Moving images contain significant temporal redundancy • successive frames are very similar

  25. Motion Estimation and Compensation • The amount of data to be coded can be reduced significantly if the previous frame is subtracted from the current frame.

  26. Block-Matching The reconstructed previous frame The current frame The predicted current frame Results of block-matching

  27. Predicted Frame and Prediction Error Predicted Current Frame Displaced Frame Difference (DFD,估測誤差)

  28. I, B and P Frames • A video sequences may contain three different types of frames: • Intra frames, (I-frames) • Predicted frames (P-frames), • Bi-directional frames (B-frames)

  29. Basic MPEG Standard Encoding order: I0, P3, B1, B2, P6, B4, B5, I9, B7, B8. Playback order: I0, B1, B2, P3, B4, B5, P6, B7, B8, I9.

  30. Coder Control Control Data Transform/Quantizer - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Motion Estimator Basic Video Encoder DFD Video in Encoded DFD Predicted current frame Reconstructed DFD Reconstructed current frame Motion Vector

  31. Basic Video Decoder Encoded DFD Predicted current frame Reconstructed DFD Encoded bitstream in Reconstructed current frame Motion vector

  32. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Motion Data Motion Estimator Video in Standards:H.261, MPEG-1, MPEG-2, H.263, MPEG-4, H.264/AVC

  33. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Motion Data Motion Estimator Video in ¼-pixel accuracy Standards:H.261, MPEG-1, MPEG-2, H.263,MPEG-4, H.264/AVC

  34. Fractional Motion Estimation

  35. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Adaptive block sizes . . . Motion Data Motion Estimator Video in Standards:H.261, MPEG-1,MPEG-2,H.263, MPEG-4, H.264/AVC

  36. Adaptive Block Size

  37. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Multiple Past Reference Frames Motion Data Motion Estimator Video in Standards:H.261, MPEG-1, MPEG-2,H.263, MPEG-4, H.264/AVC

  38. Advantages of Multiple Reference Frames

  39. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Motion Data Motion Estimator Video in Generalized B-Frames Standards:H.261, MPEG-1, MPEG-2,H.263, MPEG-4, H.264/AVC

  40. Coder Control Control Data Transform/Quantizer Quant.Transf. coeffs - Decoder Deq./Inv. Transform Entropy Coding 0 Motion- Compensated Predictor Intra/Inter Motion Data Motion Estimator Video in De-Blocking Filtering Standards:H.261, MPEG-1, MPEG-2,H.263, MPEG-4, H.264/AVC

  41. without deblock filtering with deblock filtering

  42. Comparisons (H.264 and JPEG2000) H.264 JPEG2000

  43. Comparisons (MPEG-4 and H.264)

  44. Comparisons (MPEG-4 and H.264) H.264 MPEG-4 1 Mbps

  45. Concluding Remarks • Image/Video Coding Techniques such as JPEG2000 and H.264 are able to provide high fidelity while significantly reduce bandwidth for image/video transmission. • These coding techniques therefore are effective for IPTV and/or DVB applications with limited bandwidth resources.

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